1. Field of the Invention
The present invention relates to a wireless local loop system (WLL), and more particularly, to an apparatus for and a method of allocating D-channel to minimum channel when performing a basic rate interface (BRI) in WLL, in which D-channel is allocated to the minimum channel when connection is made to V5.2 of WLL exchanger and BRI, while satisfying WLL standards, and system maintenance and extension can be easily achieved by having a modular mounting board.
2. Description of the Related Art
In general, BRI information data service is performed by WLL system, and 2B+D data has to be transmitted through B-channel, a voice band data channel, for such a service.
Specifically, total voice data processing volume from among WLL system decreases when BRI service increases, since D-channel only has 2-bit data. This is because 2-bit D-channel has to be allocated per 8-bit B-channel.
Two types of methods have been developed to process ISDN data served by WLL system and transmit the same to an exchanger; a first method is for the case where a link protocol between a radio port controller (RPC) and an exchanger is E1/V5.2, and a second method is for the case where 2W digital line connects between RPC and exchanger.
In such a conventional art, 2B+D data has to be transmitted through B-channel for processing BRI information data. However, a problem may arises in that an overall voice data processing volume decreases in WLL system when BRI service increases, since D-channel only has 2-bit data.
Therefore, it is an object of the present invention to provide an apparatus for and a method of allocating D-channel to minimum channel when performing a basic rate interface (BRI) in WLL, in which D-channel is allocated to the minimum channel when connection is made to V5.2 of WLL exchanger and BRI, while satisfying WLL standards, and system maintenance and extension can be easily achieved by having a modular mounting board.
To accomplish such an object of the present invention, there is provided an apparatus for allocating D-channel to minimum channel when BRI service is performed in WLL system, in a digital unit for combining and distributing D-channel in a radio port of WLL system, the apparatus including: a first and a second analog/digital (A/D) signal converting units for converting an analog signal input from a radio frequency unit (RFU) into a digital signal and transmitting the converted signal to RFU, and converting the received digital data to analog data and transmitting the converted signal to RFU; a first and a second modem units for code-dividing data inputted from the first and second A/D signal converting units; a channel handler/HDLC controller for searching D-channel from the data outputted from the first and second units and combining the D-channel to a single channel of 64 Kbps; a CPU for framing data received from the channel handler/HDLC controller for use of IPC communication and performing control over a block; a memory for temporarily storing variables or data, being connected to the CPU; an IPC interface unit connected between the CPU and a main processor so as to perform IPC communications; and a mux/demux for multiplexing data of 64 Kbps outputted from the first and second modem units to data of 2,048 bps.
To accomplish an object of the present invention, there is provided an apparatus for allocating D-channel to minimum channel when BRI service is performed in WLL system, in BRI interface unit for combining and distributing D-channel in a radio port controller (RPC) of WLL system, the apparatus including: a channel handler/HDLC controller for extracting D-channel from 2B+D data output from a 2W interface, performing a cycle redundancy check (CRC) on the extracted D-channel, and combining D-channel of 2-bits to a single channel of 64 Kbps; a CPU for framing data received from the channel handler/HDLC controller to allow an IPC communication and performing a control all over a block; a memory connected to the CPU and which stores temporarily variables or data; an IPC interface connected between the CPU and a main processor so as to allow an IPC communication; and mux/demux connected to the main processor and which converts 2-bit data of 64 Kbps input from the 2W interface to data of 2,048 bps.
To accomplish an object of the present invention, there is provided a method of allocating D-channel to a minimum channel when BRI service is performed in WLL system, in a process of handling D-channel of digital unit included in a radio port (RP) of WLL system, the method including the steps of: in a bottom-up handling from a terminal to an exchanger, allowing D-channel data to be available for an IPC by a CPU of the digital unit and transmitted to a main processor; transmitting to a radio port controller (RPC) D-channel which is inserted to channel No. 16 of RPC E1 interface via an IPC interface, together with D-channel data which is inserted in channel No. 16 and LAPD (Link Access Procedure on D-channel) processing data; and, when D-channel is inserted into B-channel due to a heavier loading of channel No. 16, performing LAPD process on the D-channel data together with the data inserted into B-channel, and transmitting the LAPD processed data to the RPC.
To accomplish an object of the present invention, there is provided a method of allocating D-channel to a minimum channel when BRI service is performed in WLL system, in a process of handling D-channel of a digital unit included in a radio port (RP) of WLL system, the method including the steps of: in a top-down handling from an exchanger to a terminal, analyzing D-channel data as to whether D-channel exists in channel No. 16 and transmitting D-channel data to the digital unit through an IPC interface if D-channel data is in channel No. 16; and if D-channel data does not exist in B-channel, extracting B-channel containing D-channel using a time switch by informing the main process of such a fact and transmitting the extracted B-channel to the digital unit via the IPC interface.
To accomplish an object of the present invention, there is provided a method of allocating D-channel to a minimum channel when BRI service is performed in WLL system, in a process of handling D-channel of BRI interface included in a radio port controller (RPC) of wireless local loop system, the method including the steps of: in a bottom-up handling from RPC to an exchanger, performing an IPC-process on D-channel data by CPU of BRI interface and transmitting the IPC-processed D-channel data to a main processor; transmitting 30-bit data received from the main processor to a mux/demux; extracting channel No. 16 from D-channel data input from a radio port, performing high-level data link (HDLC) protocol on the extracted channel No. 16, transmitting the result to CPU, and performing an IPC processing; in the absence of D-channel, transmitting by an IPC interface to the main processor an information of absence of D-channel and extracting and processing by the main processor a traffic channel having D-channel; in the presence of D-channel, transmitting IPC-processed D-channel and D-channel data to the main processor, transmitting by the main processor D-channel and D-channel data to a BRI interface IPC processor so as to analyze D-channel, and transmitting the result to a high-level data link controller; and dividing into 2-bit D-channel for each output port by the high-level data link controller, inserting for each channel, and transmitting 2B+D (2bit+D-channel) data to an exchanger.
To accomplish an object of the present invention, there is provided a method of allocating D-channel to a minimum channel when BRI service is performed in WLL system, in a process of handling D-channel of BRI interface included in a radio port controller (RPC) of wireless local loop system, the method including the steps of: in a top-down handling from RPC to an exchanger, analyzing D-channel data as to whether D-channel exists in channel No. 16, and transmitting D-channel data to BRI interface via 2W interface, if D-channel data exists in channel No. 16; and informing a main processor of the absence of D-channel data, if D-channel data does not exist in channel No. 16, extracting B-channel contained in D-channel using a time switch, and transmitting the extracted B-channel data to the BRI interface.